I have been appalled recently by the low quality of the debate on immigration from politicians throughout the political spectrum. Immigration defenders have claimed that immigrants do jobs Americans don’t – as if cities with few immigrants did not have garbage men. Immigration critics have said that immigrants steal American jobs. They seem to believe that the number of jobs in the economy is fixed and that one person must be getting the job at the expense of the other.

This is the lump of labor fallacy – the number of jobs in the economy is not fixed! By coming to a country immigrants increase the supply of labor and hence reduce wages. In turn, cheaper labor increases the potential return to employers to build new factories or expand their operations. In so doing, they create extra demand for workers.

The Mariel boatlift where 125,000 Cubans ended up in Miami between April 15 and October 31, 1980 provides an interesting opportunity to study the impact of a large number of immigrants on a city. A study by David Card of Berkeley showed no increase in the unemployment rate in Miami over the time period of the assimilation of the immigrants in the labor force. The Miami economy responded to influx of new labor by creating jobs to take advantage of that labor.

Inversely, when French politicians mandated a 35 hour work-week believing it would mean that companies would need more people to keep the total hours worked constant thus reducing unemployment – companies decreased the overall number of hours worked. Unemployment did not decrease.

That is not to say that immigration does not potentially have potential negative impact on certain segments of the population. Over the past 25 years wage equality has decreased in the U.S. and immigration could be partly to blame. Immigrants to the U.S. are mostly low-skilled and thus potentially pushing down the relative wages of low-skilled Americans.

David Card compared wage trends in cities with lots of immigrants such as Los Angeles, with those in places with only a few, such as Indianapolis. If immigration had a big effect on relative pay, you would expect this to be reflected in differences between wage trends. Mr. Card’s research suggests that immigrants had no significant effect on low-skilled workers’ pay. Mr. Card also tested the idea that perhaps low-skilled natives leave cities with lots of immigrants rather than compete with them for jobs, so that immigration indirectly pushes up the supply of low-skilled workers elsewhere and pushes down their wages but found no evidence that it does.

Given my personal value judgment in favor of equality of opportunity and my admiration for those willing to bear the huge fixed costs of immigration – leaving their family behind, coming to a new culture in an uncertain environment – to pursue the American dream in the land of opportunity, I am happy that empirical evidence disproves the claims that immigration is negative for this country.

For full disclosure, I am an immigrant on an H1B visa and David Card was my thesis advisor at Princeton 🙂